fix(pdfburner): correct y-position adjustment for signature seal annotations

Previously, image annotations for signature seals used a static yOffset
when combined with ink annotations, which caused positioning issues.
This change calculates the y-position of the signature annotation
relative to the next annotation and applies it only for the first seal.

- Added `yPosOfSigAnnot` calculation for precise vertical placement.
- Updated `AddInstantJSONAnnotationToPDF` to overwrite bbox.y for seals.
- Removed hardcoded ink offset logic.

EnvelopeGenerator.CommonServices/Jobs/FinalizeDocument/PDFBurner.vb

@@ -71,6 +71,7 @@ Namespace Jobs.FinalizeDocument
                 oAnnotationData.annotations.Reverse()
 
                 Dim sigAnnotType = oAnnotationData.annotations.ElementAt(1).type
+                Dim yPosOfSigAnnot = oAnnotationData.annotations.ElementAt(2).bbox.ElementAt(1) - 71.84002685546875 + 7
                 Dim isSeal = True   'First element is signature seal
 
                 Dim formFieldIndex = 0
@@ -79,9 +80,12 @@ Namespace Jobs.FinalizeDocument
 
                     Select Case oAnnotation.type
                         Case ANNOTATION_TYPE_IMAGE
-                            'Add offset to solve the seal position problem in ink signatures
-                            Dim yOffset As Double = If(isSeal And sigAnnotType = ANNOTATION_TYPE_INK, 0.07, 0)
-                            AddImageAnnotation(oAnnotation, oAnnotationData.attachments, yOffset)
+
+                            If (isSeal) Then
+                                oAnnotation.bbox.Item(1) = yPosOfSigAnnot
+                            End If
+
+                            AddImageAnnotation(oAnnotation, oAnnotationData.attachments)
 
                         Case ANNOTATION_TYPE_INK
                             AddInkAnnotation(oAnnotation)